World of Warcraft, also known as WoW, is a MMORPG (massively multiplayer online role-playing game) developed by Blizzard. World of Warcraft takes place within the Warcraft world of Azeroth, four years after the events at the end of previous Warcraft release, Warcraft III: The Frozen Throne.

The first expansion set of the game, The Burning Crusade, was released on January, 2007 and the second expansion set, Wrath of the Lich King, was released on November , 2008. The third expansion set, Cataclysm, was released on December , 2010. At BlizzCon in October 2010, Blizzard announced that there would be a fourth expansion set for the game.

With 11.4 million subscribers as of March 2011, World of Warcraft is currently the world's most-subscribed MMORPG.